A conventional white-light light emitting diode (LED) 6, as shown in FIG. 5, includes a printed circuit board 61 having a recess 611, a blue light chip 62 being mounted in the recess 611, and fluorescent glue 63 being filled in the recess 611. The blue light chip 62 can be activated to emit blue light, and the fluorescent glue 63 contains yellow fluorescent powder. With these arrangements, the blue light emitted from the blue light chip 62 can be mixed with the yellow fluorescent powder in the fluorescent glue 63 to radiate preferred white light.
While the described white-light LED 6 can emit white light by incorporating the blue light chip 62 with the fluorescent glue 63, but the color-rendering index of the blue light emitted from the blue light chip 62 and the yellow light emitted by the fluorescent glue 63 is low. As a result, the conventional white-light LED 6 is not able to preferably emit a pure white light by mixing the blue light with the yellow light in the above described manner. That means the white light emitted from the LED 6 is yellowish, a pure white light will not be achieved. Therefore, the conventional white-light LED 6 actually fails to achieve the alleged effect of emitting a white-light with high color-rendering index, and might cause discomfort to users, such as tired and sore eyes, when being used in a large quantity.